Nick Clegg, who shares Tony Blair's impatience with Britain's more flamboyant constitutional traditions, is so cross about the prospect of a bogus Queen's speech programme from Gordon Brown that he has been urging ministers to cancel Wednesday's pageant and give the 83-year-old monarch the day off.

It can't happen, of course, as the Lib Dem leader knows perfectly well. His underlying purpose is more substantive. Most of the dozen or so bills the Queen will announce – reannounce in many instances – are doomed not to be passed into law by general election day. So why not devote the 70 fag-end days of parliament to a package of constitutional reforms that will restore the tattered prestige of politics?

Brown is unlikely to be so high-minded, not least because Clegg's lunchbox is full of familiar Lib Dem sandwiches: fixed-term, four-year parliaments, proportional voting, elected Lords, sackable MPs. Cautious Brown will go no further than a promised referendum after an election.

Instead, No 10's twin priorities are to persuade wavering voters that Brown's government has not quite run out of ideas and to devise elephant traps into which he hopes David Cameron's team will obligingly hurl themselves.

Such as? A range of bills to establish quasi-legal rights and entitlements to NHS health checks and specialists, to good schools and personal tuition, to personal social care and neighbourhood police meetings, to bonus-less bankers.

Whether any of them will prove to be legally enforceable, let alone affordable under the terms of the Queen's speech fiscal responsibility bill (to halve the debt deficit by 2014), will be tested in the courts if – if – they become law by polling day. If they don't, they still serve a purpose. Wednesday's package, which Clegg dismisses as a rehearsal for Labour's manifesto, is also there to unsettle the Tories by creating dividing lines between the main parties.

It is a favourite Brown device which worked in three elections but may now be past its sell-by date. "Headline grabbing," the Tories call it; voters are no longer listening. Those Labour MPs and ministers who are still desperately plotting to oust Brown before election day privately agree. What they lack is a candidate.

But Brown is chirpier than he was two weeks ago. He unexpectedly beat off the Sun's personal attack and relishes the prospect of a bitter election campaign. He sees the Tories ahead by 41/29/19 over Labour and the Lib Dems in tomorrow's Guardian/ICM poll. Get that down to 40/30/20 and Cameron will feel real pressure on his shakier policies and people, Labour strategists predict.

Whether the media will play their role in exposing papered-over cracks is doubtful. The last time a parliament ran five years (to 1997) John Major's proclaimed optimism fooled no one. But the previous time (1992) it worked against Neil Kinnock's Labour coalition. As the simmering civil war on Europe underlines, Cameron's coalition remains shaky.

On the economy, Labour will play the experience card and point to the questionable Conservative wish to slash spending quickly – not a "smart state" strategy, Brown, Darling and Mandelson will insist. They may even try to play to anti-Murdoch sentiment by entrenching online services into the BBC's legal obligations, making it harder for Cameron to pay his debts to the media mogul.

All a self-deluding waste of time? Not entirely. The smaller Cameron's expected majority, the more circumscribed his options. The more Labour and Lib Dem MPs, the less likely it is that Labour will lurch too far left in opposition. No wonder the iconoclast Ken Clarke says that a Labour majority would be better than a hung parliament.